import java.util.*;


public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param strs string字符串一维数组 
     * @return string字符串
     */
    public String longestCommonPrefix (String[] strs) {
        // write code here
        StringBuilder s = new StringBuilder();
        if(strs.length == 0){
            return "";
        }
        for(int i = 0;i<strs[0].length();i++){
            char ch = strs[0].charAt(i);
            for(int j = 1;j<strs.length;j++){
                if(i >= strs[j].length() || strs[j].charAt(i) != ch){
                    return new String(s);
                }
            }
                s.append(ch);
        }
        return new String(s);
    }
}